Range, trailing distance and safe passing indicator for motor vehicle operators

ABSTRACT

A transparent strip has two vertically spaced reference marks inscribed thereon. The strip is attached to the windshield and by properly orienting his head, a driver aligns the image of a leading vehicle on a scale that is inscribed between the reference marks. The scale informs the driver of the distance between his vehicle and that of the leading vehicle. The strip may be positioned elsewhere on the vehicle to measure the distance of a trailing vehicle.

[ RANGE, TRAILING DISTANCE AND SAFE PASSING INDICATOR FOR MOTOR VEHICLEOPERATORS [76] Inventor: Albert M. Calvet, 1864 N. Michigan Ave.,Pasadena, Calif. 91104 [22] Filed: May 28, 1971 [21] Appl. No.: 147,782

2,960,772 11/1960 Robins 33/277 3,434,214 3/1969 Pratt 33/264 FOREIGNPATENTS OR APPLICATIONS 1,039,048 8/1966 Great Britain... 33/264 PrimaryExaminerWilliam D. Martin, Jr. Attorney-Clarence A. OBrien and Harvey13.

Jacobson [5 7] ABSTRACT A transparent strip has two vertically spacedreference marks inscribed thereon. The strip is attached to thewindshield and by properly orienting his head, a driver aligns the imageof a leading vehicle on a scale that is inscribed between the referencemarks. The scale informs the driver of the distance between his vehicleand that of the leading vehicle. The strip may be positioned elsewhereon the vehicle to measure the distance of a trailing vehicle.

7 Claims, 6 Drawing Figures [52] US. Cl 33/264, 33/277, 356/3 [51] Int.Cl G01c 21/00 [58] Field of Search 33/264, 277; 356/21, 356/3 [56]References Cited UNITED STATES PATENTS 2,881,655 4/1959 Eisenschink356/21 I mil .1 3

SHEET 2 OF 2 PATENTED NOV 20 4975 Albert M. Ca/vei INVENTOR.

RANGE, TRAILING DISTANCE AND SAFE PASSING INDICATOR FOR MOTOR VEHICLEOPERATORS The present invention relates to a simple and accurate scalefor determining the distance between two vehicles. The scale renders theinformation when an image of a trailing or leading vehicle issuperimposed on gradation marks of the scale.

BACKGROUND FOR THE INVENTION As the number of automobiles on the nationshighways increases, the occurrence of collision between trailing andleading vehicles has become dangerously frequent. A first leading causeof these collisions rests with the driver of a trailing vehicle whotailgates the leading vehicle. Thus, in many situations when the leadingvehicle brakes suddenly, by the time the trailing vehicle driver applieshis brakes, it is too late and a collision occurs. A second principalcause for auto accidents is the execution of improperly timed passing.More particularly, passing drivers sometimes fail to maintain adequatedistance between their own vehicle and a leading vehicle prior to theexecution of passing. Thus, at themoment of passing when the passingdrivers attention is diverted to the execution of his movement, theleading vehicle may stop suddenly and cause a collision with thetrailing vehicle just prior to the time the trailing vehicle hascompleted lane switch-over. Actually, little has been done to reduce thefrequency of these accidents other than enlarging brake lights on allvehicles to alert a trailing driver of sudden braking conditions.Although safety authorities have published lists of safe distancesbetween vehicles, there is no convenient method available to drivers forascertaining or measuring distances between vehicles. In essence, everydriver is left to guess at his distance and if his estimate is wrong,even the alert driver is subject to a collision despite the brake lightson a leading car.

THE PRIOR ART Several devices have been conceived for measuringdistances between vehicles. One type is the optical range finder whichworks well on apparatus such as gun sights, cameras and the like.However, to focus an instrument during driving conditions isimpractical. Although theoretically, radar devices could accuratelydetermine the distance between vehicles, this equipment is expensive andcould not be purchased by the ordinary driver. A more practical solutionto the measurement problem resides in the utilization of a transparentstrip on the windshield of a trailing vehicle. By including a scale onthe transparent strip, the image of the leading car may be superimposedupon the scale when the driver properly orients his head so that hisline of sight intersects the scale on the transparent strip as well asthe leading vehicle. Then, by determining the position of a preselectedl eading vehicle body portion relative to its position on the scale, adistance measurement from the scale can be ascertained. The problem withthese latter mentioned devices is that the image position relative to areference mark on the scale re- SUMMARY OF THE PRESENT INVENTION Thepresent invention is an improvement on the latter mentioned type ofdistance measuring device. In essence, the present invention includesseveral species that allow either a trailing or a leading vehicle todetermine the distance between it and another vehicle. Accuracy isensured by including two reference marks on a transparent strip, a scalebeing vertically disposed between the reference marks. As will bepresently explained, both reference marks must be aligned withpreselected objects so as to decrease the effect of parallax andincrease the accuracy of the measurement.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIG. 1 is an elevational view illustrating the components of a firstspecie of the invention as mounted on a trailing vehicle;

FIG. 2 illustrates the view of a trailing driver in a car equipped withthe present invention;

FIG. 3 illustrates a transparent strip as employed in the presentinvention, the strip having the image of a leading car superimposedthereon;

FIG. 4 is a partial top plan view illustrating the change in driverposition before and during a measurement;

FIG. 5 is a partial side elevational view illustrating the second specieof the present invention to determine the distance of a trailingvehicle; and

FIG. 6 is a partial sectional view illustrating a third form of thepresent invention to determine the distance of a trailing vehicle.

Referring to the drawings, reference numeral 10 generally illustrates arectangular transparent plastic strip or patch clearly illustrated inFIG. 3. As seen in FIG. ll, the strip is preferably attached to theinside of a trailing vehicle windshield 11 by utilizing a suitableadhesive. In FIG. 1, the trailing vehicle is indicated by referencenumeral 12 while a leading vehicle is indicated by 13.

As seen in FIG. 2, the strip 10 is positioned a bit to the left of thenormal line of sight that a driver maintains during operation of hisvehicle. In order to make a measurement, the driver must move his headto the left whereupon the image of leading vehicle 13 becomessuperimposed upon the strip as illustrated in FIG. 3. The superimposedimage is indicated by reference numeral 14. The strip can be fabricatedfrom cellophane, vinyl or other transparent plastic material that easilyadheres to glass. Material of this sort is frequently used in automobiledecals. Of course, instead of using a strip, marks can be directlyinscribed on the ing distance measurement. The word FEET 22 is writtenbelow the numerals 20. Inasmuch a s-safety authorities have. computedthe maximum safe speedas a. function of distance betweenvehicles,'this'correlating speed data may be included to v the rightside of the gradation marks 18. Thus, a series of numerals 24 areimprinted alongside respective distance numerals. For a given distancemeasurement one can ascertain the maximum safe speed at which hisvehicle should be driven. Reference numeral 26 indicates the word SPEEDbelow the right column of numerals 24.

A first reference mark 28 denoted as EYE LEVEL (30) requires the driverof a trailing vehicle to align the rear window of the leading vehiclewith the reference mark 28. A lower portion 32 of the strip can beserrated so that it is removable from the main strip 16. The lowerportion 32 has a second reference mark 34 thereon indicated by the wordHOOD (36). The position of this lower portion is preset so that when thereference mark 34 becomes visually aligned with the outer edge of thedrivers vehicle hood the drivers eye is at the correct distance from themain strip portion 16 to insure accuracy of measurement. As illustratedin FIG. 4, the driver usually maintains a normal position 40 fordriving. In this position, his line of sight is not obstructed by thetransparent strip 10. However, when he wishes to make a distancemeasurement to determine the distance between his vehicle and a leadingvehicle, the driver shifts to the left as indicated by reference numeral42 whereupon his line of sight intersects the strip 10. By properlyorienting his head while in position 42, the eye level reference mark 28shown in FIG. 3 will be superimposed on the rear window of the leadingvehicle image. The reference mark 34 should be visually superimposedwith the forward edge of the vehicle hood. Referring to FIG. 1, the lineof sight intersecting the eye level reference mark 28 is indicated byreference numeral 44 (FIG. 1). The line of sight intersecting the hoodreference numeral 34 is indicated in FIG. 1 as 46.

With the leading vehicle image 14 appearing as shown i FIG. 3, adetermination is made as to which gradation line 18 the bottom of theimage wheels falls on (48). In the case illustrated in FIG. 3, thereflected image indicates that a distance of 130 feet exists between thetrailing vehicle 12 and the leading vehicle 13. The speed indicationinforms the driver that if he is traveling at a speed exceeding 60 milesper hour he is maintaining a dangerous condition.

Referring to FIGS. 1, 2 and 4, an alignment member in the form of avertical rod 38 is seen to be mounted on the hood in forward alignedrelation with the plastic strip 10. This rod is utilized to render amore accurate determination of the distance between the vehicles 12 and13. The upper rod end is long enough to just meet line of sight 44. Ifthis accuracy is desired, the rod is installed on the hood and whenmaking measurements, the upper end of rod 38 should be visuallysuperimposed with the upper reference mark 28. This takes the place ofroughly determining where the upper reference 28 intersects the rearwindow of the leading vehicle. Of course, the reference marks 28 and 34and the upper end of rod 38 and the forward outer edge of the hooddefine first and second paris, respectively, of vertically spaced visualreference portions of that form of the invention illustrated in FIGS. 1through 4. The upper reference portions 28 and 38 defining the upperline of sight 44 and the second pair of reference portions including themark 34 and the forward outer edge of the hood defining the second lineof sight 46.

A second form of the invention is illustrated in FIG.

6 wherein an enlarged transparent plastic strip 50, similar in design tothe aforementioned strip 10, is vertically positioned on the rear windowof a leading vehicle. The conventional rear view mirror 52 in thevehicle has vertically spaced reference marks inscribed thereon. Theupper reference mark is indicated by 54 while the lower mark isindicated by 56. In order to determine the distance between the leadingvehicle and a trailing vehicle, the leading driver adjusts his headposition until his reflected line of sight 58 intersects the upperreference mark 54 and an upper reference mark on strip 50, such asreference mark 28 (FIG. 3). A second reflected line of sight 60 mustintersect the lower reference mark 56 on the rear view mirror 52 as wellas intersecting a lower reference mark on strip 50, such as referencemark 34 (FIG. 3). With this alignment between reference marks on therear view mirror and the transparent strip 50 on the rear window, anaccurate determined of distance (and maximum safe speed) can beascertained by noting the position of the wheels of the trailing vehicleimage on the scale of the transparent strip 50 as reflected in rearviewmirror 52.

A third embodiment of the present invention is illustrated in FIG. 5wherein a transparent strip 64, similar to that illustrated in FIG. 3,is attached to a side view mirror 62. As in the case of the transparentstrip 10 illustrated in FIG. 3, the transparent strip 64 has upper andlower reference marks 66 and 68. In order to employ the transparentstrip 64 with accuracy, index marks 70 and 72 have to be formed on theside window so that when distance of a trailing vehicle is to beascertained, the reflected line of sight 74 intersects the marks 70 and66. Of course, the marks 70 and 72 will appear respectively superimposedupon marks 66 and 68. When the visual alignment of marks is obtainedwith a superimposed image of a trailing vehicle on the scale of thetransparent strip 64, an accurate distance (and maximum safe speed)determination can be made.

Of course, it is to be appreciated that if the side view mirror 62 ismounted on a fender instead of a side door, the marks 70 and 72 shouldbe inscribed on the vehicle windshield.

A method of determining a safe passing distance between the trailingvehicle and an approaching vehicle is provided whereby the subjectdevice may be used in conjunction with a suitable table (not shown)based upon the speed of the vehicle to be passed and the speed at whichthe vehicle to be passed is overtaken.

It is anticipated that the spacings between lines 18 (FIG. 3) will havedifferent scale factors in accordance with varying parameters ofdifferent vehicle models. These parameters include the height of thedrivers eye above a roadway; the distance of a drivers eye from thewindshield; and the slope of the windshield.

It may also be desirable to employ luminescent ink on the transparentstrip which will result in better viewing at night. Regardless of thetype of print used, night viewing is made-possible by the superpositionof a vehicle silhouette on the measurement scale of'a strip. It will beappreciated that a vehicle may be equipped with two species of theinvention to allow distance measurement of trailing and leadingvehicles.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not-desired to limitthe invention to the exact construction and operation shown anddescribed, and accordinglyall suitable modifications and equivalents maybe resorted to, falling within the scope of the invention.

What is claimed as new is as follows:

1. In combination, a vehicle including a forward windshield and defininga drivers area behind the windshield, a device for measuring thedistance between said vehicle and a second vehicle spaced in front ofthe first mentioned vehicle, said device comprising first means defininga firstpair of vertically spaced visual reference portions on saidwindshield registered with a forward path of Sight of an operator insaid drivers area, second means defining a second pair of verticallyspaced visual reference portions disposed forward of said windshield andspaced apart a greater vertical distance than the vertical distancebetween said first pair of reference portions, the upper referenceportions of said first and second means being generally horizontallyaligned and the lower reference portion of said second means beingdisposed at a lower elevation than the lower reference portion of saidfirst means, said lower reference portions being positioned relative tothe upper reference portions so that a line of sight extending betweenthe upper reference portions intersects with a line of sight extendingbetween the lower reference portions at a viewing point disposed in saiddrivers area at substantially eye level therein, one of said meansincluding means defining a distance scale extending between thecorresponding reference portions, whereby the registry of the image ofsaid second vehicle, when viewed from said viewing point, on said scalewill correctly indicate the distance between the first mentioned vehicleand said second vehicle when said vehicles are disposed on a straightroad surface.

2. The structure of claim 1 wherein the lower reference portion of thesecond means comprises the outer hood edge of the-first mentionedvehicle.

3. The structure of claim 1 together with indicia on the scale whichrepresents maximum safe speed as a function of distance.

l. An assembly for measuring the distance from a leading vehicle to atrailing vehicle comprising a transparent patch secured to the rearwindow of the leading vehicle, the patch having vertically separatedreference marks inscribed thereon, a distance scale inscribed on thepatch between the reference marks, and a rear view mirror mounted in theleading vehicle for reflecting the image of the patch, the mirror havingvertically separated index marks respectively lined up in visualsuperposition with the reference marks, whereby the position of thereflected image of the trailing vehicle on the scale indicates thedistance between vehicles.

5. A device for measuring the distance from a leading vehicle to atrailing vehicle comprising a transparent patch secured to the side viewmirror of a leading vehicle, the patch having vertically separatedreference marks described thereon, a distance scale described on thepatch between the reference marks, vertically sepa' rated index markslocated on a side window adjacent the side view mirror for respectivevisual superposition with the reference marks whereby the position ofthe reflected image of the trailing vehicle on the scale indicates thedistance between vehicles.

6. The structure of claim 5 together with indicia on the scalerepresenting maximum safe speed as a function of distance.

7. A device for measuring the distance from a leading vehicle to atrailing vehicle comprising a transparent patch secured to the side viewmirror of a leading vehicle, the side view mirror being mountedforwardly of the vehicle windshield, the patch having verticallyseparated reference marks inscribed thereon, a distance scale inscribedon the patch between the reference marks, vertically separated indexmarks located on the drivers side of the windshield, the index marksbeing visually superimposed on respective reference marks, whereby theposition of the reflected image of the trailing vehicle on the scaleindicates the distance between

1. In combination, a vehicle including a forward windshield and defininga driver''s area behind the windshield, a device for measuring thedistance between said vehicle and a second vehicle spaced in front ofthe first mentioned vehicle, said device comprising first means defininga first pair of vertically spaced visual reference portions on saidwindshield registered with a forward path of sight of an operator insaid driver''s area, second means defining a second pair of verticallyspaced visual reference portions disposed forward of said windshield andspaced apart a greater vertical distance than the vertical distancebetween said first pair of reference portions, the upper referenceportions of said first and second means being generally horizontallyaligned and the lower reference portion of said second means beingdisposed at a lower elevation than the lower reference portion of saidfirst means, said lower reference portions being positioned relative Tothe upper reference portions so that a line of sight extending betweenthe upper reference portions intersects with a line of sight extendingbetween the lower reference portions at a viewing point disposed in saiddriver''s area at substantially eye level therein, one of said meansincluding means defining a distance scale extending between thecorresponding reference portions, whereby the registry of the image ofsaid second vehicle, when viewed from said viewing point, on said scalewill correctly indicate the distance between the first mentioned vehicleand said second vehicle when said vehicles are disposed on a straightroad surface.
 2. The structure of claim 1 wherein the lower referenceportion of the second means comprises the outer hood edge of the firstmentioned vehicle.
 3. The structure of claim 1 together with indicia onthe scale which represents maximum safe speed as a function of distance.4. An assembly for measuring the distance from a leading vehicle to atrailing vehicle comprising a transparent patch secured to the rearwindow of the leading vehicle, the patch having vertically separatedreference marks inscribed thereon, a distance scale inscribed on thepatch between the reference marks, and a rear view mirror mounted in theleading vehicle for reflecting the image of the patch, the mirror havingvertically separated index marks respectively lined up in visualsuperposition with the reference marks, whereby the position of thereflected image of the trailing vehicle on the scale indicates thedistance between vehicles.
 5. A device for measuring the distance from aleading vehicle to a trailing vehicle comprising a transparent patchsecured to the side view mirror of a leading vehicle, the patch havingvertically separated reference marks described thereon, a distance scaledescribed on the patch between the reference marks, vertically separatedindex marks located on a side window adjacent the side view mirror forrespective visual superposition with the reference marks whereby theposition of the reflected image of the trailing vehicle on the scaleindicates the distance between vehicles.
 6. The structure of claim 5together with indicia on the scale representing maximum safe speed as afunction of distance.
 7. A device for measuring the distance from aleading vehicle to a trailing vehicle comprising a transparent patchsecured to the side view mirror of a leading vehicle, the side viewmirror being mounted forwardly of the vehicle windshield, the patchhaving vertically separated reference marks inscribed thereon, adistance scale inscribed on the patch between the reference marks,vertically separated index marks located on the driver''s side of thewindshield, the index marks being visually superimposed on respectivereference marks, whereby the position of the reflected image of thetrailing vehicle on the scale indicates the distance between vehicles.